Altitude · about five minutes
It does not go wrong on day one.
Day one you are fresh and the adrenaline covers a lot. The guides who run high-country elk hunts will tell you the trouble starts on day three.
Where it actually breaks
The problem at altitude is generally not an inability to hunt hard on the first day. Most people manage that. It is the third, fourth and fifth days where hunters falter, and once you are properly tired at altitude it is harder to come back from it than it would be at home.
That is worth sitting with, because almost all the preparation advice people follow is about being able to do the first day. Being able to repeat it is a different problem.
Water is weight, so people ration it
Guidance for backcountry days is roughly three litres in typical conditions and five in hard ones. Carrying five litres is carrying five kilograms, so in practice people ration, and the rationing is rarely a decision anyone makes consciously.
Dehydration then arrives in a fairly predictable order: headache first, then nausea, then fatigue, then cramps, and at the far end heat exhaustion. The early stages are easy to attribute to simply being tired, which is why they get missed.
Cold makes you drink less, not more
This is the part that surprises people. Cold exposure reduces how much you voluntarily drink, through several mechanisms at once.
- Thirst sensation is blunted in the cold, so the signal you rely on gets quieter.
- Cold-induced diuresis: peripheral vasoconstriction raises central blood pressure, and the kidneys shed what they read as a surplus.
- Dry air raises respiratory water loss, which you cannot feel at all.
- Water freezes, and gets voluntarily restricted because stopping to deal with it is a nuisance.
At altitude there is more: reduced antidiuretic hormone and elevated atrial natriuretic peptide both push urine output and sodium excretion up. You are losing more while feeling less inclined to replace it.
Altitude sickness is a medical condition, not a hydration problem. It can begin as low as 5,000 feet and most commonly presents around 8,000, starting with headache and moving to dizziness, vomiting, fatigue and disturbed sleep. Its early symptoms overlap dehydration almost exactly, which is a good reason to take it seriously rather than to assume you know which one you have. Nothing we make prevents or treats it, and anyone telling you their drink does is worth walking away from.
What this changes
If the failure point is day three rather than day one, then what matters is what you can sustain, not what you can survive once. That is a different question from the one most preparation answers, and it is the question we built for.
We are not going to claim a drink fixes a five day hunt. What we will say is that the thing being asked of you on those days is repetition, and that the losses which accumulate quietly are the ones worth planning around.
Sources
- Flat Tops Wilderness Guides, physical preparation for high-altitude wilderness elk hunts
- Frontier Safety and Supply, backcountry dehydration and daily water requirements
- Rocky Mountain Elk Foundation, altitude sickness in elk hunters
- National Academies, fluid balance and voluntary dehydration in cold and high-altitude environments